In general, an intrusion detection system of a vehicle can detect illegal intrusion into a vehicle by irradiating an ultrasonic signal in a vehicle through a transmitting end and converting ultrasonic waves into an electrical signal and analyzing a signal level of the electrical signal upon detecting ultrasonic waves colliding with and reflected by an object at a receiving end.
Such an indoor intrusion detection system for a vehicle detects scattering, that is, the Doppler effect due to movement of an intruder and an object, determines whether an intrusion occurs, and generates an alarm according to the determination result in the case of vehicle intrusion.
The vehicle intrusion detection system for a vehicle is mainly operated in a door locked state in which the vehicle is not driven.
Conventionally, an indoor space of a general sedan is not large, and thus it is possible to detect an entire area using an ultrasonic sensor including one ultrasonic transmitter and one ultrasonic receiver.
However, in the case of a vehicle with a large internal space, such as a bus, there is a problem in that vehicle intrusion cannot be completely detected using only an ultrasonic sensor including one ultrasonic transmitter and one ultrasonic receiver. Accordingly, conventionally, a plurality of ultrasonic sensors are installed in a vehicle so as to detect vehicle intrusion.
However, when the number of ultrasonic sensors increases, there is a problem in that vehicle manufacturing costs increase and current consumption in a vehicle standby state is increased.